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Subject: Re: archos as a cd changer

Re: archos as a cd changer

From: Fernando Birra <>
Date: Thu, 1 Apr 2004 13:12:18 +0100

Hi again,

>"jobarjo" <> escreveu na mensagem
> maybe you should just forget the 6 cd organisation? When you press 'CD6'
> button, does the HU automatically displays 'cd number 6' or is it the
> rockbox that tells it the number to display?

When I press CD6 on the headunit a message request to switch to CD6 is sent
to the AJB. I need to acknowledge the request but I think I can send a reply
telling that instead of CD6 we are in CD1 or any other CD number. The text
is displayed by the headunit it self. However it uses the contents of the
message replyed from the CD changer to display the right numbers. For
instance, imagine we pressed CD 5 but the CD changer finds errors on in and
reverts to the previous CD. The headunit displays whatever we tell it that
we are playing. The format is however fixed to one digit per disc number and
2 digits per track. The display is in the form: CD X-YY.

> whatever, if you press 'CD6' twice, does the rockbox receive 2
> notification of the cd6 button?

In that case only one request is sent to the rockbox. The headunit is a
little bit inteligent and it finds that we are switching to the current disc
so no action is needed.

> In this case you just map these actions as standard rockbox buttons. you
> just have to post an entry in the button_queue. the rockbox will do the
> rest.
> this way you have the entire rockbox behaviour through your HU. maybe
> you could use the talkbox feature also?

I see... To tell you the truth, having to memorize what each button
represents doesn't atract me. Also, the problem that the headunit filters
the key presses imposes additional restrictions. I thought of using the scan
(Play Intro) button to virtualize the the 6 Cds. Let's say I would switch
intro play mode twice in a short period (1-2 seconds). This could be mappe
to play discs 7-12. The problem is that the available set of headunit
buttons that we can use is not large enough. Apart from the disc access
buttons (1-6) that have the problem I mentioned, there is a Scan (Intro)
button and a Random button, apart from the Previous and Next Tracks.

Thinking better now, perhaps some of the 6 direct disc access buttons could
be used for whatever I wish. Suppose I press button 3, I could reply that we
are still inside CD1 and that way, a second press on the same button would
generate the event again... Maybe the HU can be fooled ;)

Now, suppose I map HU keys to rockbox buttons. I would need a way to receive
feedback. Although I can also display text on the HU display, this can only
be done while the HU is in idle mode. The HU is used to display the time and
so there is a button that toggles from FM or CD display to Clock display. To
display a message on the HU display I simply change a message as if I were
some other component on the bus letting the HU know the current time (a time
broadcast message to be more specific). The message is limited to 7 chars
and I have beed using this facility to debug. However, as soon as I press a
key on the HU the display mode will switch to Normal Mode (CD or RADIO
display modes) and any feedback text that I would like to display will only
be visible after 5 or 6 seconds of inactivity. I guess the talkbox feature
could help in this situation. I've been working hard on this and I have
missed most of the discussions about this feature. What can it do? I suppose
it plays some pre-recorded clips as a feedback right? Could it be used to
"read" folder names (even if we need to store an mp3 file inside each

> another advantage is that the buttons are still available and there is
> no 'cd changer mode' it can cohabit easily.
> you can look in serial.c and button.c in the firmware dir.

The jukebox buttons are still available (as I said, I exit this special mode
if I press the STOP button). The only thing that is missing are the remote
buttons because I need to reprogram the Rx pin to my own purposes. Of
course, as you suggest, the jukebox could be simultaneously operated on the
HU and on its keypad...

Fernando Birra

Received on 2004-04-01

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